Massive amplification of rolling-circle transposons in the lineage of the bat Myotis lucifugus
Massive amplification of rolling-circle transposons in the lineage of the bat Myotis lucifugus
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DOI：
10.1073/pnas.0609601104
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发表时间：
2007-02-06
影响因子：
11.1
通讯作者：
Feschotte, Cedric
中科院分区：
文献类型：
--
作者：
Pritham, Ellen J.;Feschotte, Cedric
滚环转座子（Rolling-Circle transposons，RC）是一类新近发现的真核生物转座因子，广泛存在于植物、无脊椎动物和斑马鱼的基因组中。我们提供的哺乳动物基因组的Helitrons，这是以前没有报道的殖民化的证据。我们确定了两个家庭的Helitrons lucifugus的小棕色蝙蝠。第一个家族的共有序列HeliBat 1显示出自主Helitron的特征，包括编码具有RC复制基序的约1，500-aa蛋白的能力和与SF 1超家族DNA解旋酶相关的区域。HeliBatN 1家族是一个非自主的Helitron家族，与HeliBat 1只有远亲关系。这两个HeliBat家族已经获得了高拷贝数（分别约为15，000和> 100，000拷贝），并至少占M. lucifugus基因组。序列分歧和跨物种分析表明，这两个HeliBat家族在过去大约30-36百万年内扩增，并仅限于晚祷蝙蝠的谱系。我们不能检测到Helitrons的存在下，在任何其他顺序的胎盘哺乳动物，尽管这些类群在数据库中的广泛代表性。我们描述了一个实例，他/iBat介导的转导宿主基因片段，随后分散在整个M约1,000个拷贝。lucifugus基因组。鉴于RC转座子介导细菌和玉米中宿主基因的复制和改组的倾向，人们很容易推测，晚祷蝙蝠中Helitrons的大规模扩增影响了这些哺乳动物的进化轨迹。
Rolling-circle (RC) transposons, or Helitrons, are a newly recognized group of eukaryotic transposable elements abundant in the genomes of plants, invertebrates, and zebrafish. We provide evidence for the colonization of a mammalian genome by Helitrons, which has not been reported previously. We identified and characterized two families of Helitrons in the little brown bat Myotis lucifugus. The consensus sequence for the first family, HeliBat1, displays the hallmarks of an autonomous Helitron, including coding capacity for an approximate to 1,500-aa protein with an RC replication motif and a region related to the SF1 superfamily of DNA helicases. The HeliBatN1 family is a nonautonomous Helitron family that is only distantly related to HeliBat1. The two HeliBat families have attained high copy numbers (approximate to 15,000 and > 100,000 copies, respectively) and make up at least approximate to 3% of the M. lucifugus genome. Sequence divergence and cross-species analyses indicate that both HeliBat families have amplified within the last approximate to 30-36 million years and are restricted to the lineage of vesper bats. We could not detect the presence of Helitrons in any other order of placental mammals, despite the broad representation of these taxa in the databases. We describe an instance of He/iBat-mediated transduction of a host gene fragment that was subsequently dispersed in approximate to 1,000 copies throughout the M. lucifugus genome. Given the demonstrated propensity of RC transposons to mediate the duplication and shuffling of host genes in bacteria and maize, it is tempting to speculate that the massive amplification of Helitrons in vesper bats has influenced the evolutionary trajectory of these mammals.